Cluster computing systems comprise a set of computers configured to process portions of a computing job. Computers may be added to the cluster or removed from the cluster as the demand changes. The resource load on a computer cluster for processing database system jobs can be extremely spiky, as large jobs come and go. When a request for a large job is received, preparing the cluster to perform the large job can take a great deal of time, as computers may need to be added to the cluster to perform processing at the desired rate, and data for processing may need to be transferred to the worker machines. This slowdown lowers the overall efficiency of the cluster and its ability to process large jobs on demand